LinuxCNC Support Forum :: Topic: Analogue input (2/2)

NEWS

LinuxCNC 2.5.2 Release

LinuxCNC 2.5.2 Update Released (changelog).

LinuxCNC 2.5.1 Release

LinuxCNC 2.5.1 Update Released (changelog). If the Package Manager does not prompt you to upgrade see this page.

LinuxCNC 2.5.0 Release

New major release (changelog). See the instructions to update your system from EMC 2.4 to LinuxCNC 2.5.

Home

Forum

HAL

HAL Components

Analogue input

Welcome, Guest

Page:
1
2

TOPIC: Analogue input

Re:Analogue input 04 Feb 2012 16:27 #17409

jmelson
OFFLINE
Moderator
Posts: 268
Thank you received: 10
Karma: 31

andypugh wrote:

There might be some clues here:
wiki.osdev.org/Sound

This looks more relevant:
tldp.org/LDP/lpg/node84.html
And seems to indicate that ioctl() is the way to get low-level access

I think sound cards are AC coupled, so won't work for slowly-changing inputs.
ioctl() only permits a privileged program to gain access to I/O registers.
The wav interface to the sound card moves blocks of raw samples in and
out, not a single sample a a time.

Jon

The administrator has disabled public write access.

Re:Analogue input 04 Feb 2012 19:55 #17411

skunkworks OFFLINE Moderator Posts: 33 Thank you received: 2 Karma: 6	I am using an arduino to measure spindle temp and offset z automagically.. I followed these examples.. emergent.unpythonic.net/01198594294 works very well so far electronicsam.com/images/KandT/testing/S...on%20HM2-Servo-1.png sam
	The administrator has disabled public write access.

Re:Analogue input 05 Feb 2012 10:47 #17440

cmorley
OFFLINE
Moderator
Posts: 1493
Thank you received: 40
Karma: 89

DIY oscilloscope using a sound card.
It seems 0 -.05 volts would be safe but others have used up to aprox 5 volts (but an AC current not DC)
They recommend a voltage divider to keep voltage to a reasonable number.
If you had an old sound card hanging around might be interesting project ....

www.micahcarrick.com/pc-sound-card-oscilloscope-linux.html
www.yann.com/en/diy-turn-your-gnulinux-c...cope-29/09/2010.html

The administrator has disabled public write access.

Re:Analogue input 06 Feb 2012 17:47 #17477

davidmp OFFLINE Fresh Boarder Posts: 2 Karma: 0	Thank you every body for your replies. I didn't know the audio inputs were AC coupled. This will make it not work for my purposes so... Does anybody have any ideas for a small DAQ that can be read through the RS232 or Ethernet ports and display values on AXIS? Thanks
	The administrator has disabled public write access.

Re:Analogue input 06 Feb 2012 23:38 #17479

andypugh OFFLINE Moderator Posts: 4140 Thank you received: 141 Karma: 130	davidmp wrote: Thank you every body for your replies. I didn't know the audio inputs were AC coupled. Actually, they very often are not AC coupled. You ought to be able to find out if yours are using Audacity and a signal source. Matlab has a function that can use the sound card for IO, so it is practical.
	The administrator has disabled public write access.

Re:Analogue input 07 Feb 2012 00:44 #17480

dab77 OFFLINE Gold Boarder Posts: 199 Karma: 6	skunkworks wrote: I am using an arduino to measure spindle temp and offset z automagically.. I followed these examples.. emergent.unpythonic.net/01198594294 works very well so far electronicsam.com/images/KandT/testing/S...on%20HM2-Servo-1.png sam +1 Arduino is a very simple way to achieve DC analog readings.
	The administrator has disabled public write access.